Thermostatic switch



Nov. 2 1926. 1,605,313

T. c. WHITEHEAD THERMOSTATIC SWITCH Filed Dec. 10. 1923 2 Sheets-Sheet l l l, I

Nov. 2 1926. 1,605,313

. T. c. WHITEHEAD THERMOSTATIC SWITCH Filed Deo. 10, 1923 2 Sheets-Sheet 2 Patented Nov. 2, 1926.

THOMAS C. WHITEHEAD, 0F DETROIT, MICHIGAN.

THEaMosTATIc SWITCH.

Application led December 10, 1923. Serial No. 679,829.

This invention relates to refrigerating apparatus and refers more particularly to thermostatically operated means for controlling the operation of a motor driven pump used for supplying a refrigerating medium to a refrigerator.

An object ofthe invention is to provide a simple and practical electric switch that is adapted to be operated by a reliable thermostat for opening and closing an electric circuit to the motor.

Another object is to provide simple and practical means for adjusting the operating connection between the thermostat and switch so that the thermostat will operate the switch at any desired temperature.

With the above and other objects in view, the invention consists of certain novel features of construction, combination and arrangement of parts as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawing Figure 1 is a sectional side elevation of a control mechanism embodying my invention;

Figure 2 is a sectional view taken on line 2 2 of Figure 1;

Figure 3 is a top plan view of the construction illustrated in Figure 1 with the cover removed;

Figure 4 is a side elevation of a slightly modified construction;

Figure 5 is a sectional view taken on line 5 5 of Figure 4;

Figure 6 is a view similar to Figure 1 but showing a slightly modified form of construction Figure 7 is a top plan View thereof.

Referring now to the drawing in which like characters of reference designate corresponding parts throughout the several views, the numeral l designates a thermostat which is preferably in the form of an eX- y pansible metallic chamber or bellows 2 that is mounted on an enlargement 3 of a base 4, and that is in communication with a suitable fluid inlet opening 5 in the base. The chamber 2 is preferably closed at its upper end by a plate 6 and is preferably detachably secured at its lower end by a flanged nut 7 to the enlargement 3 of the base.' Located within the chamber 2 is a vertical tubular guide 8 that is preferably formed integral with the venlargement 8 of the base and that preferably surrounds a stem 9 projecting downwardly from the plate 6. Suitable openings 10 areformed in the guide 8 at the lower ends thereof so that the iuid entering the opening 5 may pass into the chamber 2.

For controlling the opening and closing of the electric circuit to a motor (not shown),I preferably provide an electric switch 11 that is mounted above the thermostat between a pair of spaced walls 12 extending upwardly from the top 13 of a frame 14 mounted on the base. For operatively connecting the switch to the thermostat I preferably provide a rod 15 that projects upwardly from the plate 6 and that is connected by a pivot pin 16`to a pair of U-shaped electric contact members 17 which are adapted to connect a pair of spaced electric terminals 18 secured to the walls 12. A coil s ring 19 is preferably terminally secure to the spaced arms of the contact members 17 intermediate the ends thereof and normally retains the outer ends of the contact members in raised position, while a pair of spaced pins 20 preferably extend between the walls 12 and are adapted to limit the upward movement of the contact members.

With the construction as described, the vapor tension of the iuid within the chamber 2 will cause the expansion and contraction of the chamber corresponding to temperature changes. Thus, the rod 15 and contact members 17 will be either raised or lowered.

In order that the contact members 17 will snap into engagement with the terminals 18 when the rod 15. is raised incident'to a rise in the temperature, I preferablyprovide a pair of spaced Ifulcrum pins 21 which eX- tend between the spaced walls 12 and which are preferably located adjacent to the pins sin 20 so that after the rod 15 moves upwardly a certain distance,'the pins 21 will be engaged by the contact members 17 and will cause the outer free ends thereof to be swung below the pivot pin 16. The outer ends of the contact members will then be moved downwardly suddenly by the spring 19V into engagement with the terminals 18 to close the electric circuit to the motor.

For disconnecting the contact members 17 from the terminals 18 when the rod 15 is lowered incident to a fall in temperature, I preferably provide a pair of spaced fulcrum pins 22 which extend between the spaced walls v12 but which are preferably located adjacent to the terminals 18 so ,thatfiafter the rod moves downwardly a certain distance the pin 22 will be engaged by the contact members 17 and will cause the outer ends thereof to be swung upwardly above the pivot pin 16. The outer ends" of the contact members will then be moved upwardly suddenly by the spring 19 against the pins 20 to open the electric circuit to the motor. L

In order that the switch may be operated at any desired temperature, the pin 16`is adapted to be adjusted within a slot 23 extending longitudinally of the rod 15 so that the point at which the contact members 17 will snap into or out of engagement with the terminals 18 may be readily varied. Suitable nuts 24 are preferably threaded on the rod 15 for accomplishing the adjustment.

. A coil spring 25 preferably surrounds the rod 15 between the plates 6 and the top 13 of the frame 14 for opposing the expansion of the chamber 2, while a suitable cap 26 is preferably placed over the walls 12 to cover the switch.

In Figures 4 and 5, I have shown a slight modification in which a coil spring 30 is preferably located within an eXpansible chamber 31 to provide a more compact construction. One end of the spring 3() engages a flange 32 at the upper end of a guide 33 in which a stem 34 reciprocates, while the other end of the spring rests upon the arms of a spider 35. The spider is preferably detachably secured to an extension 36 of the stem, while the arms thereof are adapted to move within elongated slots 37 in the guide 33. With this construction, the base 38 is preferably provided with a relatively large opening 39 through which the sprin 30 and spider may be removed if desire However, this opening is normally closed by a suitable plug 40 that is preferably provided with a fluid inlet opening 41.

The chamber 31 is connected by a rod 42 to an electric switch 43 so that when the chamber expands or contracts according to variations in temperature of the fluid supplied thereto through the opening 41, the

switch 43 will be operated to either openor y closthe electric circuit to the motor.

In Figures 5 and 6, Iv have shown another slight modification in which the electric switch is preferably provided with a single contact member 81 that is preferably pivoted at one end upon a post 82 extending upwardly from the top 83 of the supporting frame 84. At the outer free end of the contact member 81 is a reduced portion 82 upon which is preferably removably mounted a suitable sleeve 83 for establishing an electrical connection between a pair of spaced electric terminals 84 secured to a projection 85 upon the top 83 of the frame.

In order that the sleeve 83 on the Contact member 81 will snap into or out of engagement with the terminals 84', I preferably provide a coil spring 86 that is terminally connected to an eye 87 on the contact member 81 and to an eye 88 on the base of a U- shaped arm 89 which isl preferably connected to the upper end of a thermostatically operated rod 90. The post 82 is preferably of such a length that the pivot 91, connecting the U-shaped arm 89 to the rod 90, is normally below the pivot 92 connecting the contact member 81 to the post 82, consequently, the free end of the contact member 81 will be normally retained in raised position by the spring 86. As soon as-the rod is raised, due to the expansion of the chamber 93, the U-shaped arm 89 will be rocked upon its pivot. When the base 94 of the U-shaped arm reaches a point below the pivot 91, the spring 86 will move the free end of the contact member 8l downwardly so that the sleeve 83 will snap into engagement with the terminals 84 and close the electricl circuit tov the motor Y (not shown). The spring 86 will then retain the contact member in lowered position until the base 94 of the arm 89 is raised by the rod 90 above the pivot 92, whereupon the spring will return the contact member to normal position.

' While it is believed that from the foregoing description, the nature and advantages of the invention will be readily apparent, I desire to have it understood that I do not limit myself to what is herein shown and described and that such changes may be resorted to when desired as fall within the scope of what is claimed.

What I claim as my invention is:

1. In a control mechanism, the combination with a base, a hollow frame surmountinof said base, an electric switch surmounting said hollow frame, a pressure responsive control element for said switch within said frame, an actuating connection between said element and switch, a spring within said frame opposing movement of said control element in one direction and means surmounting said frame enclosing 'said switch at its top and opposite sides.

2. In a control mechanism, the combination with a frame, a pair of electric terminals on said frame, a longitudinally actuable rod, a pair of electric contact arms pivoted upon said rod'and engageable with said terminals, a yieldable member connecting'said contact arms, means engageable with said arms between their ends to cause said yieldable member to move said arms into engagement with said terminals, and means also engageable with said arms between `their ends to cause said yieldable member to disengage said arms from said terminals.

3. In a control mechanism, the combinalll() tion with a base, of Aa thermostat on said base, a frame on said base, a rod projecting from said thermostat, a pair of electric terminals on said frame, a pair of electric contact arms pivoted upon said rod and engageable with said terminals, a yieldable member connecting said contact arms, pins engageable with said arms to cause said yieldable member to move said arms into engagement with said terminals, and pins also engageable with said arms to cause said yielolable member to disengage said arms, from said terminals. f

4. In a control mechanism, the combination with an expansible chamber and a base to which one end of said chamber is secured, of a guide member projecting into said chamber from the bther end thereof, a coacting guide member secured to said base and projecting into said chamber, abutments carried by the free end portions of said guide members, and a spring compressed between said'abutments, resisting expansion of said chamber.

`by the opposite end of said chamber, one of said guide members being longitudinally slotted, an abutment carried by the free end portion of said slotted guide member,`and

an abutment carried by the other guide member and projecting through said slot, and a spring compressed between said abutments.

6. In a control mechanism, the combination with a member actuable substantially rectilinearly of a pair of switch arms copivotal upon said member, a spring connecting said arms, contacts engageable by the free end portionsof said armsy in one limiting position of said arms and abutments engageable by intermediate portions of said arms, through actuation of said supporting members to effect .swinging of said arms about their common pivot.

7. In a control mechanism, the combination with a longitudinally actuable rod having a slot extending in a threaded portion thereof, of a pivot member mounting upon sald rod 1n said slot, a pair of switch arms` copivotal upon said pivot member and eX- tending at opposite sides of said rod, a spring urging said arms convergently, contact members engageable bythe arms in a limiting position thereof, and a nut upon the threaded portion of the rod for adjustingsaid pivot member.

8. In a control mechanism, the combination with an expansible chamber, of members 'projecting into said chamber from opposite ends thereof, having guiding engagement one with the other, and a spring mounted upon one of said members within the chamber and acting upon the other of said members to resist expansion of said chamber.`

9.' In a control mechanism, the combination with a longitudinally actuable rod, of a pair of fixed contacts at opposite sides of said rod, a pair of switch arms pivoted upon said rod and oppositely projecting from the rod for engagement with said contacts, a spring connecting said arms for alternatively urging the arms into or out of engage` ment with said iixed contacts, a pair of stop members limiting travel of the arms responsive to said spring away from said contacts, and a pair of fulcrum members engageable by said arms while clear of said contacts for reversing the divergence of the arms to permit engagement of the arms with the fixed contacts by said spring.

In testimony whereof I aix my signature.

THOMAS C. WHITEHEAD. 

